Leeway switching and tuning system



Oct. 27, 1936. R. c. CURTIS LEEWAY SWITCHNG AND TUNING SYSTEM Filed Sept. 27, 1935 Tzu-5-2 istics.

Patented Oct. 27, 1936 UNITED STATES LEEWAY SWITCHING AND TUNING SYSTEM Richard C. Curtis, East Orange, N. J., assignor to Wired Radio, Inc., New York, N. Y., a corporation of Delaware Application September 27, 1935, Serial No. 42,385

3 Claims.

This invention pertains in general to electrical control means and specifically relates to a form of switching and tuning apparatus particularly adapted for use in radio receiving systems.

One of the objects of my invention consists in providing an arrangement for effecting a definite change-over operation from one predetermined tuning condition to another while permitting a certain leeway adjustment of a selected condition.

Another object resides in the provision of apparatus for changing from one tuning condition to another and for concomitantly rendering effectively inoperative the audible reproducing system of associated receiving apparatus during the change-over from one condition to another.

A still further object of the invention comprises providing means for interdependently effecting predetermined changes from one tuning condition to another in a radio receiver or like apparatus and providing adjustment for each selective condition while at the same time performing other controlling operations associated with a change in tuning conditions.

These and other objects will be apparent from the following, reference being had to the accompanying drawing in which:

Fig. 1 is a fragmentary elevation of a portion of a radio receiving organization disclosing one embodiment of the leeway switching and tuning system of my invention;

Fig. 2 is a view of the mechanical operating parts of the arrangement shown in Fig. l;

Fig. 3 is a vertical Sectional View of the embodiment shown in Fig. l; and

Fig. 4 is a schematic circuit of the electrical organization associated with the system of my invention.

This invention contemplates an arrangement for effecting a predetermined shift from one position to another of apparatus such as used for tuning radio receiving equipment to render the same responsive to various selected program frequency bands of discrete frequency character- In accordance with the invention, these shifts from one position to another are effected in accordance with a definite predetermined mechanical action produced by a mechanical arrangement which permits of a certain latitude of adjustment in the tuning apparatus for each of the selected program bands, thereby permitting accurate adjustments for optimum signal receiving conditions, It is a feature of this system, that this arrangement also avoids undesirable audible disturbances by rendering effectively inoperative the audible reproducing apparatus during the shifting operation from one tuning position to another. At the same time, the apparatus selectively coordinates an indicia mechanism for visually indicating the selected Station to the op- (Cl. Z50-20) erator, such mechanism being operatively conditioned in accordance with the shifting process of the tuning mechanism.

Referring to the drawing in detail, the panel I forms part of a radio receiving organization, such as may be used for the reception of wired radio programs wherein programs are transmitted by a plurality of discrete carrier frequencies over Wire lines. The panel I is provided with a subpanel 2 having an indicator window 3 mounted therein. On the panel 2, below this indicator window, a selection control knob 4 is provided, while below the sub-panel 2 a volume control knob 5 is provided.

Referring to Fig. 3, the knob 4 is mounted upon a shaft 'I which is mechanically connected with the rotor of a variable tuning capacitor 8 which controls the program selection of the radio receiver. Referring to Figs. 2 and 3, a detent rotor III is freely mounted upon the shaft I and is provided with a key-way I I in which a key-pin I2 extends from the knob 4. The key-pin I2 is rigidly fixed to the knob 4 and, due to the size of the key-way II, the knob 4 and the shaft 'I are permitted a certain latitude of angular movement before the key-pin I2 engages with either side wall of the key-way II of the rotor Ill. In accordance with this arrangement, the variable capacitor 8 is susceptible to adjustment within certain limits, due to movement of the knob 4, Without causing accompanying movement of the rotor I0. However, when the knob 4 is angularly moved in excess of this latitude of movement, the pin I2 engages either side wall of the keyway I I of rotor I0 whereupon the rotor I0 is angularly moved.

In the position shown in Fig. 2, the lower periphery of the rotor I0 is provided with detent recesses I5 which correspond to different angular positions of the rotor of the variable capacitor 8 which render the receiving organization responsive to the different discrete program carrier frequencies for the reception of selected programs. The detent recesses I5 are peripherally engaged by the rider element I8 of a detent dog I9, pivotally mounted on a mounting bracket 20. The mounting bracket may be secured to a portion of the chassis of the radio receiving organization. The dog I9 is provided with an extending lug 23 which engages with a resilient element portion 24 of a switch unit 25. The resilient portion 24 of the switch unit 25 exerts a force against the lug 23 to cause the rider I8 to continuously peripherally engage the recesses I5 of the rotor I0 to cause the rotor I0 to assume definite predetermined angular positions.

A translucent indicia plate 3U is mounted upon the rotor I0 in juxtaposition with the window 3 so that various opaque indicia appearing on the dial Will be visible at the Window 3 When illuminated by a lamp 32 mounted upon an upwardly extending portion of the member 20. The indicia provided on the dial 30 represents, in the present instance, letters of the alphabet, each letter corresponding to one predetermined position of the rotor I0 and also corresponding to the settings of the capacitor B which render the receiver responsive to various program frequencies.

Referring to Fig. 4, the capacitor 8 is represented as forming part of the receiver 39. A volume control potentiometer 40 is associated with the output circuit of the receiver 39 and is connected with a translating device or loud speaker unit 4 l. The switch 25 has one pair of contacts 42 connected in shunt with the potentiometer 40 and another pair of contacts 43 connected in the circuit extending from the power supply of receiver 39 to the lamp 32.

In the operation of the system of my invention, when the receiver 39 is in operative condition, the lamp 32 is normally illuminated so that a particular program channel, such as represented by the character C, is visible through the window 3 as shown in Fig. l. In this condition of the apparatus, the knob 4 may be moved to permit adjustment of the variable capacitor 8 to effect the best tuning condition for the reception of that particular program. During this adjustment, the other parts of the system of the invention remain unaffected.

When it is desired to shift the receiver reception to another program channel, the knob 4 is moved sufficiently so that the pin I2 causes the movement of rotor l0 to a selected position. The detent dog i9 operates to bring the rotor into a selected predetermined position in which position the knob 4 may be adjusted within a certain latitude, as before pointed out, to effect the minute adjustment of the capacitor to effect proper tuning conditions for the reception of the further selected program panel.

During the movement of the knob 4 from one program channel position to another, the angular movement of the dog I9, due to the rotation of the rotor I0, causes the lug 23 to actuate switch 25. The actuation of switch 25 causes the contact pair 42 to be closed and the contact pair 43 to be opened, respectively. This operation of the switch 25 therefore results in a short circuiting of the potentiometer 40 and an interruption in the energizing circuit to the lamp 32. Consequently, when the knob 4 is being shifted from one program panel position to another, the loud speaker 4I is disabled and the operation of lamp 32 is interrupted. As a result of this, the radio receiving organization is rendered eifectively inoperative for the production of audible sounds during a shifting operation, thereby eliminating any annoying or undesirable audible effects, and at the same time the indicia on the dial 30 is rendered visible only at the time that the shifting mechanism comes into operative position for the selection of a particular station. This latter operation gives the effect of each of the indicia characters suddenly coming into View at the indicia window, due to the on and ofi condition of the illuminating lamp therefor.

Although I have shown a preferred form of the leeway switching and tuning system of my invention, it will be understood that various changes and modifications may be made Without departing from the intended scope of my invention. I do not, therefore, desire to limit myself to the foregoing except as may be pointed out in the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A tuning system comprising, a tuning device, shifting means for causing said device to assume any one of several separate definite positions in a tuning operation, each of said positions lying within different predetermined ranges corresponding to different signalling frequency bands to which said tuning device may be adjusted by movement thereof, indicia means moveable by said shifting means and having spaced characteristics thereon corresponding respectively to said predetermined different ranges, means for rendering said indicia means effective for indicating purposes only at times when said tuning device is in one of its said positions, detent means for holding said indicia means in any one of its indicating positions, and means for permitting a limited angular motion of said shifting means and said tuning device while said indicia means is held immovable in any of its indicating positions.

2. A tuning system comprising, an angularly moveable tuning element, shifting means for causing said element to assume any one of several definite angular positions in a tuning operation, each of said positions lying Within different predetermined ranges corresponding to different signalling frequency bands to which said tuning element may be adjusted by movement thereof, translucent indicia means movable by said shifting means and' having spaced characteristics I thereon corresponding respectively to said predetermined different ranges, means for rendering said indicia means effective for indicating purposes only at time when said tuning element is in one of its said positions, detent means for holding said indicia means in any one of its indicating positions, means for permitting a limited angular motion of said shifting means and said tuning element While said indicia means is held immovable in any of its indicated positions, a lamp for illuminating said indicia member and a switch operated by said detent means for controlling a circuit to said lamp to render the same operative only during times when said indicia means is held in any of its indicating positions.

3. A tuning system comprising, a tuning element, shifting means for causing said element to assume any one of several definite positions in a tuning operation, each of said positions lying within different predetermined ranges correspending to different signalling frequency bands to Which said tuning device may be adjusted by movement thereof, indicia means moveable by said shifting means and having spaced characteristics thereon corresponding respectively to said predetermined different ranges, means for rendering said indicia means effective for indicating purposes only at times when said tuning element is in one of its said positions, a detent rotor associated with said indicia means, detent means cooperating with said detent rotor for holding said indicia means in any one of its indicating positions and means for permitting a limited angular motion of said shifting means and said tuning element While said indicia means is held immovable in any of its indicating positions.

RICHARD C. CURTIS. 

